1. Field of the Invention
The present invention relates to a printer control apparatus, a printing control method, and a printing control system.
2. Description of the Related Art
There have been known printing control systems in which a host-side control apparatus and a printer-side control apparatus are connected by a Universal Serial Bus (USB) interface.
In such printing control systems, communication between a host (a host control apparatus) and a device (a device control apparatus) that have a master-slave relationship is controlled and, when data is to be transmitted from the device side to the host side, the device side is not allowed to transmit the data to the host side until a transmission request signal from the host side is received on the device side. The host side does not know when data to be transmitted is generated on the device side, and accordingly needs to send a transmission request signal regularly to the device side.
The host side in the systems described above also needs to regularly send a check request signal to the device side in order to check the error status on the device side regularly. Receiving the check request signal, the device side transmits a response signal to the host side.
A known technology of this type is to regularly transmit from a host to a printer apparatus (a device control apparatus) a signal that indicates that the connection between the host and the printer apparatus is in a normal state.
However, printing control systems of the related art have a problem in that increasing the frequency of transmission of the signal that is transmitted regularly from the host slows down the overall communication speed of the system. Decreasing the frequency of transmission gives rise to an opposite problem in that the amount of data waiting to be transmitted builds up, which causes troubles such as a loss of data to be transmitted from the device and the shutting down of the device.
For those reasons, a printer control apparatus, a printing control method, and a printing control system that are capable of improving the overall communication efficiency of a system have been waited for in the technical field of the present invention.